These mattresses have orthopaedic characteristics which can be divided into two categories: biomechanical characteristics and microclimatic characteristics.
The biomechanical characteristics relate to the elasticity of the mattress, its tensile strength and its resistance to pressure. Said characteristics serve as the basis (to be completed with further criteria deriving from combined analysis) for defining the performance of the mattress, when subjected to pressure by people with different weights and body sizes.
The microclimatic characteristics typically relate to resistance to humidity and thermal capacity, that contribute to the development of a given contact temperature and humidity between a mattress and a person lying thereon.
In addition to having the orthopaedic characteristics mentioned above, the known mattresses must also be fireproof, hypoallergenic, anti-decubitus (they must prevent and cure bed sores), easy to wash, at least at 60° C. and highly breathable, particularly in the contact area with the user or the patient.
There are currently several types of known mattresses, also known as sanitary mattresses, that adopt different technical solutions.
One of the more known solutions is the memory foam mattress, namely manufactured with a viscoelastic polyurethane foam which deforms with the weight and heat of the human body. These mattresses memorise the shape of the body and as a consequence deform. When the weight is removed, the mattress quickly regains its original shape.
An alternative to the memory foam mattress is the latex mattress, made with natural latex processed in order to provide a foam material to which elasticity and strength are added, by means of a vulcanisation process.
Other types of mattresses also exist, such as, for example, the water-foam mattress (also known as water foamed mattress, made through a polyurethane foam treatment process), the bagged spring mattress, the three-dimensional polymer (or 3D polymer) mattress, normally made of polyester polymer, or the mattress known as anti-decubitus with forced air ventilation. This latter mattress is normally entirely protected by a breathable three-dimensional cover.